Method and apparatus for sewing angular seams



United States Patent [72] Inventors AloisKucera;

Vilem Hlavon, Brno, Czechoslovakia [21] Appl. No. 881,789

[22] Filed Oct. 30, 1969 Continuation-impart of application Ser. No. 735,507, June 6, 1968, abandoned.

[45] Patented Dec. 8,1970

[73] Assignee ElltexZavody Textilniho Strojirenstvi,

(leneralni Reditelstvi, Brno, Czechoslovakia [3 2] Priority June 7, l 967 [3 3] Czechoslovakia [31 1 No. PV4l50-67 [54] METHOD AND APPARATUS FOR SEWING ANGULAR SEAMS 11 Claims, 17 Drawing Figs.

[52] US. Cl. 112/164, 112/184,112/233,112/262,112/221 [51] lnt.Cl. D051) l/l2, D05b 57/14 [50] Field otSearch l 12/ 184, 181, 182, 163, 164, 167, 233, 232, 262, 221

[56] References Cited UNITED STATES PATENTS 593,735 11/1897 Colley 112/164X 1,591,319 7/1926 Johnson 112/184X 2,854,936 10/1958 Nicolay 112/164 3,381,642 5/1968 Bond 112/233 Primary Examiner-H. Hampton Hunter Attorney-Michael S. Striker ABSTRACT: Formation of a loop of a bottom thread at the apex of an angular seam requiring turning of the fabric, is prevented by braking the bobbin and temporarily supplying a piece of the bottom thread by resiliently displacing a movable control means supporting the leading end of the bottom thread for movement along a path which is shortened in the displaced position of the guide means.

PATENTED DEE 8197B sum 2- OF 8 PATENTED DEC 8 I978 sum 3 BF 8 INVENTORE? PAIENTEDDEB 81978 sum 5 u; 8

INVENTORB TTORNE 1 METHOD AND APPARATUS FOR S EWING ANGULAR SEAMS REFERENCE TO A RELATED APPLICATION BACKGROUND OF THE INVENTION When double or multiple angular seams are made by a sawing machine having two or more needles for forming two or more parallel seams, an undesired loop is formed by the bottom thread whose seam is interrupted before the turning of the fabric to another position, as required for angular seams. During this operation, only one needle can sew a seam, and the direction of the seams is changed. Since the respective other needle is inoperative shortly before the turning of the fabric and during the sarne, while the first needle continues to make a few stitches toward the corner of the workpiece, the bottom thread is withdrawn from the bobbin of the other needle at a length corresponding to the length of the seam sewn by the working needle. When the working needle arrives at the corner of the workpiece, the machine is stopped at a position in which the working needle penetrates the workpiece, the presser foot is released, and the workpiece is turned an angle corresponding to the angle of the corner of the workpiece which is to be provided with double seams, and the machine is again started so that the working needle continues the seam until the inoperative needle arrives again at the sewing point where its operation was interrupted, and can continue to stitch the respective seam at the apex of the angle of the two seam portions. Consequently, the unwound length of thread, which was not used for making a seam, now forms a loop at the apex of the angular seam. r y

In accordance with the prior art, the unwound andunused extra length of the bottom thread at the apex of an angular seam, and forming a loop, is cut off and removed, which is detrimental for the appearance of the finished workpiece, and involves additional costs to a degree noticeable in mass production.

The length of the loop depends on the number of stitches made by the operating needle while the other needle was held inoperative.

SUMMARY OF THE INVENTION It is one object of the invention to eliminate loop formation at the apex of angular seams;

Another object of the invention is to provide a method and apparatus for making multiple angular seams requiring turning of the workpiece, without unwinding undesired bottom thread portions from the bobbins.

Another object of the invention is to stop unwindingof the bottom thread from a bobbin at the apex of an angular seam, and to temporarily let out a compensating portion of the bottom thread which is resiliently withdrawn before the angular seam is continued.

With these objects in view, a method according to the invention comprises the steps of sewing by first and second needles on a fabric at least first and second parallel seams with first and second bottom threads and top threads, resiliently supporting the leading portion of the first bottom thread, stopping sewing of the first seam, blocking the supply of the first bottom thread while continuing sewing the second seam so that the resiliently supported leading bottom thread portion is fed out, turning the fabric, continuing the second seam so that the first seam in the new turned position moves toward said first needle whereby the resiliently drawn out bottom thread is pulled back so that no loop is formed, and releasing the blocked supply of the first bottom thread.

An apparatus according to the invention preferably comprises a bobbin rotatably mounted on a bobbin casing and holding a wound up supply of a bottom thread which is subjected to an unwinding force during sewing, a control means 2 r A mounted on the bobbin casing for movement between a normal position for guiding the leading portion of unwound bottom thread toward a sewing point along a path, and a displaced position in which the path of the bottom thread is shortened, and resilient means for biasing the control means into the normal position, brake means mountedon the bobbin casing for movement between a normal inoperative position, and a braking position blocking rotation of the bobbin so that the bobbin thread cannot be unwound from the bobbin by the unwinding force, and operating means for moving the brake means from the normal position to the braking position when no bottom thread is required. Consequently, the unwinding force acting on the bottom thread tensions the leading portion of the same whereby a force is exerted on the control means and the same is urged into the displaced position in which a part of the leading portion of the bottom thread is first released and after turning of the fabric again withdrawn since the force exerted by the leadingportion of the bobbin thread on the guide means is reduced and the control means is returned by the resilient means to the normal position.

In the preferred embodiment of the invention, the bobbin casing has an annular wall formed with a circumferential cutout, and the control means is segment-shaped and located in the cutout and movably mounted on the bobbin casing. A spring has one end secured to the bobbin casing and the other end secured to one end of the segment-shaped control means,

. while abutting the annular wall along the length thereof so that tion and its method of operation, together with additional objectsand advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWING FIG. I is an axial sectional view illustrating a bobbin casing according to the invention in an empty condition without a bobbin;

FIG. '2 is a plan view, partially in section illustrating the bob- .bin casing of FIG. 1;

FIG. 3 is a front elevation, partially in section, illustrating an embodiment of the invention;

FIG. 4 is a fragmentary sectional view illustrating a detail of the bobbin casing;

FIG. 5 is a fragmentary sectional view illustrating the action of the brake means on the bobbin;

FIG. 6 is a diagram illustrating the making of angular double seams in accordance with the prior art whereby a loop is formed of a bottom thread when the workpiece is turned an angle corresponding to the angle of a corner thereof;

FIG. 7 is a plan view, partially in section, and illustrating operating means for the brake means of the bobbin;

FIG. 8 is a fragmentary vertical sectional view of a sewing machine illustrating operating means for a pair of needles;

FIG. 9 is a fragmentary elevation illustrating manual means for rendering the needles selectively inoperative;

FIG. 10 is a fragmentary elevation illustrating a detail of FIG. 8;

FIG. 11 is a fragmentary elevation illustrating a detail of FIG 8; y

FIG. 12 is a plan view illustrating a displaced position of resilient control means; and

FIG. 13 to FIG. 17 are schematic perspective views illustrating successive positions of needles and fabric during the making of angular seams at the corner of a fabric.

DESCRIPTION OF THE PREFERRED EMBODIMENT The illustrated apparatus will be described with reference to a sewing machine having twin needles for making two parallel seams, but it will be understood that the invention can be applied to sewing machines having a greater number of needles for making parallel seams, and if required angular seams.

Referring first to FIG. 3, the gripper or rotary hook I is carried by a vertical drive shaft 2 supported for rotation in bearing bushings 3 of a supporting structure 4, also shown in FIG. 7. A bobbin casing 6 is mounted in the interior of the gripper l and has a central cylindrical hollow shaft portion 7 supporting a bobbin 8 for rotation. A supply of bottom thread 9 is wound up on bobbin 8. As also shown in FIG. 1, a resiliently arrested arm 7a, mounted on a pivot 7b retains bobbin 8 in bobbin casing 6, but permits replacement of the bobbin. Shaft 2 carries a gear which is driven by another gear, not shown, for rotating shaft 2 with gripper 1. I

As best seen in FIGS. 1, 2 and- 4, bobbin casing 6 has a circular wall formed with a cutout 10 extending over part of the circumference of the circular wall of bobbin casing 6. A part circular substantially segment-shaped control member 11 is mounted in cutout 10 and guided in the same for circumferential movement between a normal position, and a displaced position. A hole 12 passes through control member 11. A first groove 13 is formed in control member 11 extending from hole 12 toward the upper edge of control member 11, and is continued by a groove 14 in bobbin casing 6 in the normal position of control member 11 shown in FIGS. 1 and 2.

A bottom thread 9 unwound from bobbin 8 has a portion 9a located within the bobbin casing, a portion 9b passing through hole 12, and a portion 90 extending from hole 12 substantially in opposite direction to portion 9a and out of the bobbin casing 6, guided by groove 14, and by the forked end of a leaf spring 16 which is secured to control member 11 by a screw 15. An adjusting screw isthreaded into a bore of control member 11 and can be adjusted for varying the braking force exerted by leaf spring 16 on the bottom thread portion 90. Leaf spring 16 has a hole into which one end of a coil spring 17 is hooked. Coil spring 17 abuts the outside of the circular wall of bobbin casing 6 and has a corresponding curved shape. The other end of coil spring 17 is hooked into a hole 19 of the wall of bobbin casing 6 so that spring 17 holds control means ll, 16 in the normal position illustrated in FIG. 2. The leaf spring 16 has the additional function of holding control member 11 properly positioned in cutout 10 of the bobbin casing. In order to further mount control member 11 in the guide recess 10, a foot member 21, fastened to control member 11 by a rivet 22, guides control member 11 by slidingly abutting two circular shoulders 6a and 6b, see FIG. 4, which also slidingly guide the leaf spring 16 so that control means 11, 16 are guided on the wall of bobbin casing 6 for circumferential movement.

In the normal position shown in FIG. 2, bottom thread 9 is unwound from the bobbin by an unwinding force produced by the moving fabric, and thread portions 9a, 9b, 9c slide through hole 12 while bobbin 8 turns.

As will be explained hereinafter in greater detail, the bobbin can be braked by a brake member 33 shown in FIGS. 5 and 7, so that the unwinding force acting on portion 90 cannot turn the bobbin, but acts in the region of hole 12 on the control member 11 to resiliently displace the same against the action of spring 17 to a position in which the length of the leading thread portion 9a, 9b, 9c between bobbin 8 and the fabric is reduced. and a part of the same is fed out to the sewing point on the fabric without any bottom thread being unwound from the bobbin.

Referring now to FIG. 7, a bracket 'is secured by screws 23, 24 to support 4. Bracket portion 25 carries a journal pin 26 on which an arm 27 is mounted. Arm 27 has two wall portions 27a connected by a pivot pin 30 on which an angular lever 31 is mounted for angular movement. Bowden cable means 29 are secured to arm 27 and mounted on bracket 25. A spring 28 abuts arm 27 and bracket 25 to urge arm 27 to turn in counterclockwise direction, and when the Bowden cable 29 is operated, arm 27 is turned in clockwise direction. A leaf spring 35 is secured by a screw 36 to a portion of arm 27 and has an end resiliently abutting the leg 31a of angular lever 31 so that the end of leg 31a abuts a shoulder 34 on support 4. The other leg of angular lever 31 carries a brake arm 33 secured by rivets 32. When arm 27 is in the normal position due to the action of spring 28, brake arm 33 releases bobbin 8. When one of the needles is stopped, Bowden cable 29 is operated, as described below, to turn arm 27 clockwise so that shaft 30 with lever 31 is moved toward the bobbin casing 6 and leg 31a is displaced by shoulder 34 of support 4 so that lever 31 is rotated around pivot shaft 30 to a position in which brake member 33 abuts bobbin 8 and blocks rotation of the same so that no bottom thread 9 can be unwound.

The Bowden cable cooperates with the means by which the needle is retracted, and when the needle is again rendered operative and Bowden cable means 29 is released, arm 27 is turned by spring 28 to its normal position so that lever 31 is pressed by spring 35 to an inoperative position in which no braking effect is exerted on bobbin 8 by brake arm 33 and the bottom thread 9 can be freely unwound from bobbin 8.

Apparatus permitting by one manual operation, simultaneous braking of a bobbin and retraction of the respective nee dle to an inoperative position, will now be described with reference to FIGS. 8 to 12. A sewing machine 40 has a pair of first and second needles 41 and 42. The needles are mounted on corresponding needle bars 43, 44 and perform a vertical reciprocating motion in guiding frame parts 45, 46. Each needle bar carries a spring-biased pawl 47, 48 which are turnable about pivots 49, 50 and have such a shape as to be engaged during movement in one direction by a drive member 51, and during movement in the opposite direction by fingers 52, 53 of a disc segment 54 which is mounted for rocking movement.

Drive member 51 is mounted on.a body 55 and performs during the operation of the machine, a continuous vertical reciprocating motion derived from a crank rod 56 mounted on a pin 57 of a crank arm 58 turning with a drive shaft 59. A guideway 60 guides slide body 55, on which drive member 51 is mounted, for vertical movement.

The disc segment 54 is mounted for pivotal movement in the region of the upper positions of pawls 47, 48, rockable about a pivot 61, and coupled to manual operating means including lever arms 62, 63 secured to a shaft 64, lever 63 being pivotally connected with a link 65 articulated to an arm 66 which is secured to a shaft 67 operated by the manual lever 68.

Manual lever 68 is mounted on the front surface of the sewing machine 40, while lever means 65, 63 are mounted in the rear of the machine housing. Arm 62 is also located in front of the machine.

As best seen in FIG. 9, manual lever 68 can be placed in angular positions by which it is arrested by a spring loaded arresting pin 69 cooperating with arresting holes 70.

When manual lever 68 is placed in one of its end positions, as shown in FIG. 8, disc segment 54 is turned a corresponding angle so that its nose 52 is placed in the path of reciprocating movement of pawl 47 which near its upper terminal position engages nose 52 of disc segment 54 and is first angularly displaced and then gripped by nose 52 so that the needle bar 43 is arrested in an upper position in which needle 41 is inoperative. In order to assure a reliable engagement and arresting of pawl 47, or 48, by the noses 52 or 53 of disc segment 54, pawls 47, 48 have suitable shaped contact surfaces. When, for example, pawl 47 is engaged by nose 52 of segment 54, pawl 47 is turned to such a position that it is disengaged from drive member 51 and is held by nose 52 together with the needle bar and the needle 41 which is in this manner retained in a retracted position located above the fabric, not shown.

When manual lever 68 is turned to its central position, disc segment 54 is turned so that nose 52 releases pawl 47 which is angularly displaced and then caught by drive member 51 so that the needle bar is from then on vertically reciprocated. Consequently, when manual lever 68 is in the central position, both needle bars 43, 44 and needles 41, 42 perform a corresponding reciprocating motion for making two seams. When manual lever 68 is shifted to one ofits end positions, as may be required by the sewing operations to be carried out, one of the needles 41 or 42, respectively, is inoperative and located above the fabric.

As best seen in FIG. 10, an arm 66 is attached to shaft 67 which carries manual lever 68, and has articulated links 71, 72

to which Bowden cables 29, 29a are respectively attached.

The ends of Bowden cables 29, 29a from which the movement of arm 68 is transmitted to lever means 27, are secured to the rear of the machine housing 40 and located in the interior of housing 40 connected with the lever means 27 27a, as shown in FIG. 1 1.

As has been explained with reference to FIG. 7, operation of one of the Bowden cables 29, 29a effects movement of the brake means 33 to a braking position, when at the same time, the respective needle bar and needle is arrested in anupper inoperative position. i

It is evident that each needle 41 and 42 is capable of making a seam of top and bottom threads, each of the bottom threads being supplied by a braked bobbin, as explained above with reference to FIG. 2 and FIG. 7.

When an angular seam is to be sewn, it is necessary to render one of the needles 41'or 42 temporarily inoperative.

This is accomplished by placing manual lever 68 in one of its end positions so that one of the Bowden cables 29, 29a pulls the corresponding lever means 27 toward the gripperor rotary hook I so that the brake means 33 becomes operative.

thread, it acts on the leading thread portion 9a, 9b, 90, see

FIG. 2, to move the control means 11, 16 to a position in which the path between the bobbin and the sewing point on the fabric is shortened since part of the doubled up leading portion 9a, 9c is fed out while control means ll, 16 is resiliently displaced against the action of spring 17. Breaking of the blocked bottom thread in the braked bobbin cannot take place due to the resilient yielding of control means 11,

16. The displacement of control means 11, 16 is just sufficient to let out enough bottom thread as is required by the movement of the fabric between points 1h and 1c.

is turned and the first needle continues to sew the seam to The braking of bobbin 8 which supplies the bottom thread 9 depends on the disengagement of the respective needle, ir-

\ respective in which manner the braking member 33 is actuated. Instead of the describedmechanical operating means for the brake means 31, 33, an electromagnetic brake replacing Bowden cable 29, or acting directly with a movable armature on the surface of bobbin 8 could be used.

Referring now to FIG. 6, assuming that two needles make parallel seams la and lb, and that the same 1a has to be continued to a point 1c and then continued to a point It! so that an angular seam is formed, while, the second seam 1b has to be continued to a point 1e and then further continued to a point If in order to form a second angular seam, for example along the corner of a fabric, the needle making the seam lb is retracted at the point 1e while the needle making seam 1a is continuously operated to point lc where it is placed in a position piercing the fabric. The fabric is now turned about point 1a, and the respective needle continues to make a seam to point 1g where the point 1e of the fabric is again located under the needle which has made the seam lb. This needle is rendered operative, and both needles continue to make the seams to the points If and 1d. In accordance with the prior art, some bottom yarn is unwound by the second needle during the relative displacement of the first needle from the point It! to the point 1c of the moving fabric, and due to the turning of the fabric, a loop 11' is formed of the bottom thread of the second needle during the movement of the fabric from point 10 to point lg. Formation of this loop is prevented in accordance with the present invention.

At the moment when the second needle is at the point 1e and is retracted to an inoperative position, the Bowden cable 29 is automatically operated to displace arm 27 and to move brake means 31, 33 to the operative position in which bobbin 8 of the second needle is braked and blocked so that no bottom thread 9 can be unwound from the same.

While the first needle continues to make a seam from point 1h to point 10 and then from point It to point lg after turning of the fabric, the bobbin of the second needle remains braked and blocked but a pull is exerted on the bottom thread 9 of the respective bobbin. Since this force cannot unwind the bobbin point 1g while control means 11, 16 is gradually withdrawn by spring 17 to its initial position pulling back the previously let out part of the leading portion of the respective bottom thread until the normal position shown in FIG. 2 is again as sumed by the bobbin casing and control means of the second needle when the same is rendered operative at the point la for continuing its seam 1f. Consequently, in the arrangement of the invention, no loop li will be formed. At the point Ie, the respective second needle begins to cooperate with the bobbin in a normal manner by unwinding the bottom thread from the turning bobbin without displacing the control means 11, 16. The force of spring 17 in each of the bobbin casings of the two needles is selected so that the control means ll, 16 remain in the normal initial position during sewing of straight seams since the unwinding force is smaller than the force required for displacing guide means 11, 16 against the action of spring 17, unless the respective bobbin is blocked by brake means 31, 33 under control of the operator when making of a pair of angular seams required by the shape or contour of the work.- piece.

The operation of the control means 11, 17 during the sewing of a double seam along the corner of a fabric, for example a shirt collar, will now be described in detail with reference to FIGS. 13 to 17.

FIG. 13 shows the position of a pair of needles 41 and 42 after making an angular double seam along the cornerof the fabric 75. l

FIG. 14 shows fabric 75 in an initial position in which the two needles 4l and 42 sew two seams alongthe edge 0 of a workpiece or fabric spaced from the edge a distance a. At this moment, the needles penetrate the fabric at point L, and P,, and the fabric is moved by the feeding means of the sewing machine in the direction S so that the needles approachthe other edge 0, of the fabric. The point P, is spaced from the edge 0, the same distance as from the edge 0.

At this point, it is necessary to withdraw needle 42 by operation of manual lever 68 so that needle 42 is held by the disc segment 54 in a high inoperative position. Needle 41 may also be located above the fabric 75.

In the position of FIG. 15 needle 41 is operative and sews a continuation of its seam from point L, to point L due to the fabric movement. At the same time, the fabric, moving in the direction S, places needle 42 above the: point P so that a piece of bottom thread is required between the points P, and P Since the respective bobbin 8 was braked by brake means 32 when needle 42 was withdrawn by operation of manual lever 68, the bobbin cannot supply this part of the bottom thread, which is paid out by control means 11. which resiliently gives due to the pull on portion of the bottom thread.

When point L is spaced the same distance a from the fabric edge 0, as from the fabric edge 0, the fabric is turned about needle 41 to the. position shownin FIG. 16. The fabric is turned in the direction S until edge 0, is located in the direction in which the fabric is fed. Consequently, continuous operation of needle 41 will produce a seam parallel to the fabric edge O, to the point L shown in FIG. 17.

In the position of FIG. 16, the other seam and point P, has been placed in a new position so that further feeding movement of the fabric will move the point P, towards needle 42 and bobbin 1]. The length of the part of bottom thread 9 which was let out by the resilient yielding of control member position shown in FIG. 2. When needle 42 is above point P shown in FIG. 17, it can be lowered to an operative position by turning manual lever 68 to its central position, by which also release of the brake means 33 is effected, so that bottom threads for both needles are from now on supplied by unwinding the same from the respective bobbins 8. Due to the fact that the free bottom yarn portion is first resiliently pulled out and then resiliently withdrawn, no loop, as shown at ii in FIG. 6, can be formed at the point l in FIG. 17, so that the object of the invention is obtained.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of arrangements for sewing angular seams differing from the types described above.

While the invention has been illustrated and described as embodied in a method and apparatus for preventing the formation of a loop of a bottom thread at the apex of an angular seam produced by a twin needle sewing machine, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the'present invention.

We claim:

1. The method of sewing multiple angular seams, comprising the steps of moving a fabric in one direction; sewing by first and second needles at least first and second parallel seams having first and second top and bottom threads, respectively; resiliently supporting the leading portion of said first bottom thread while supplying said first and second bottom threads; stopping sewing of said first seam by said first needle; stopping the supply of said first bottom thread while continuing sewing said second seam so that said resiliently supported leading bottom thread portion is resilientlydrawn out by said first needle while said fabric moves and said second needle operates; turning said fabric about said second needle so that said seams are placed in new positions; continuing said second seam so that the end of said first seam in said new position moves toward said first needle whereby said resiliently drawn out bottom thread portion is resiliently pulled back so that no loop of surplus thread is formed of said bottom thread during the time that sewing of said first seam is stopped; releasing said stopped supply of said first bottom thread; and continuing both said first and second seams.

2. The method of claim I wherein said fabric is turned an angle less than 180 after stopping of sewing said first seam at a point of said fabric; and wherein said first seam is continued at said point of said fabric after turning of said fabric whereby continuous first and second angular seams without a bottom thread loop are produced.

3. Apparatus for sewing multiple angular seams in a fabric, comprising, in combination, supply means including a bobbin casing, and a bobbin rotatably mounted in said casing and holding a supply of a bottom thread which is subjected to a unwinding force of a moving fabric during sewing; thread control means mounted on said casing for movement between a normal position for guiding the leading portion of unwound bottom thread along a path toward a sewing point in the fabric, and a displaced position in which said path is shortened; resilient means on said casing for biasing said control means into said normal position; brake means mounted on said casing for movement between a normal inoperative positionand a braking position blocking rotation of said bobbin so that said bottom thread can not be unwound from said bobbin by said unwinding force; and manual operating means for moving said brake means from said normal inoperative position to said braking position when no bottom thread is required so that the unwinding force acting on said bottom thread tensions said leading portion of the same whereby a force is exerted on said thread control means so that said control means is urged into said displaced position and releases a part of said leading portion until upon angular turning of said fabric the force exerted on said control means by said leading portion of said bottom thread is reduced and said control means is returned by said resilient means to said normal position so that the released part of said leading portion is retracted whereby no loop is formed of said bottom thread.

4. Apparatus as claimed in claim 3 wherein said bobbin casing has an annular wall formed with a circumferential cutout; wherein said control means includes a control member located in said cutout; and wherein said control member is mounted on said bobbin casing for circumferential movement.

5. Apparatus as claimed in claim 4 wherein said control member is segment-shaped, and said resilient means includes a spring having one end secured to said bobbin casing and the other end secured to one end of said segment shaped control member, said spring abutting said annular wall and having a curved shape.

6. Apparatus as claimed in claim 4 wherein said control means include a leaf spring secured to said control member at one end and having another end for guiding said leading portion of said bottom thread.

7. Apparatus as claimed in claim 4 wherein said control member has a hole for the passage of said leading portion of said bottom thread from said bobbin to said sewing point; said bobbin, said hole and said sewing point, being in such a relative position so that said path is angular and the direction of said leading portion is substantially reversed at said hole.

8. Apparatus as claimed in claim 7 wherein said control member has a guide groove for said leading portion and extending from said hole, and wherein said bobbin casing has a guide groove for said leading portion forming a continuation of said guide groove in said control member.

9. Apparatus as claimed in claim 3 wherein said manual operating means include a pivotally mounted arm means; wherein said brake means include an angular lever mounted on said arm means for turning movement and having one end abutting said bobbin casing in said normal inoperative position of said brake means, said brake means further including a brake member mounted on said lever and abutting said bobbin in said braking position and being spaced from the same when said lever abuts said bobbin casing, a spring mounted on said arm means for urging said lever to abut said bobbin casing; said operating means including manually operated means for moving said arm means with said lever and said brake member so as to move said brake means between said inoperative and braking positions.

10. Apparatus as claimed in claim 9 wherein said manually operated means include Bowden cable means connected with said arm means and manually operable for moving said arm means to a position in which said brake means is in said braking position, and spring means acting on said arm means for moving the same to another position in which said brake means is in said inoperative position.

11. Apparatus as claimed in claim 3 comprising first and second needles having inoperative positions, and operative positions for sewing first and second seams of first and second top and bottom threads; wherein said supply means include first and second: bobbins, control means, resilient means and brake means; wherein said manual operating means selectively displace said first and second needles together with said first and second brake means and move one of said first and second needles to said inoperative position and the correlated brake means to said braking position so that operation of the other needle and movement of the fabric causes release of the leading portion of the respective bottom thread by the correlated one control means until the fabric is turned whereupon during to said operative position and the respective brake means is released to said normal inoperative position. 

